Re: Multiple documents

[Jim Parker <hopeye cfl rr com>]

First of all let me describe what I am doing.  My program is a 3D 
modeler used as a front end for engineering computations, such as 
Computational Fluid Dynamics and Finite Element Analysis, etc..  This 
means it is real similar to what you would expect to find in a typical 
CAD package.

I am using a notebook widget to display multiple views of the object.  
Typically I would have front view, side view, top view, and isometric.  
Each view has a seperate notebook page.  I am not doing WiW, because on 
a typical monitor, the image within the window is too small to do 
anything useful.

The current model will be displayed in all the notebook pages that were 
created.  Opened but non-current models will not be displayed and will 
be pointed to by my linked list of struts.  In other words, only one 
model is displayed at a time, but several may be opened and in memory.  
Changes to any view are automagically updated in all other views with 
an expose_event call.

Now I hope you understand why I designed my program they way I did.  
BTW, I am using OpenGL for the display engine, and this will affect the 
my choice of variables in the struct, but it typically includes stuff 
like scale, rotation angles, drawing primative lists, layers, parts, 
etc.

I also have a global struct where I keep my program wide variables.  
This is where I store the address of the current model.  So a typical 
call would look like:

        gtkcad->current_model->some_variable

I use a dialog box to switch models.  The workings behind this are just 
a simple search using the GTK+ API, then putting the returned address 
in the above mentioned variable and redrawing the window(s).

Like I said it works for small numbers of open drawings, but I can see 
performance issues if hundreds of drawings were opened.

Let me know if you need more details.  I will be off-line some because 
I am moving, but will try to answer your questions as soon as possible.

cheers,
Jim Parker



On 2003.08.26 11:15 Chris Garrett wrote:
> Hi,
>
> That is pretty much the way I thought I would have to do it.  
> However, I am experiencing some confusion about how to ensure that 
> callbacks from the canvas end up resulting in changes on the correct 
> image.  I havent written any code for multiple documents yet, since I 
> am still thinking about the design of the structures etc.
>
> I also need to consider a way for multiple views of the same document 
> to be updated whenever changes are made...  I think the structs will 
> have a lot of links in them so it is easy to pull out the ones needed 
> in any given circumstance!
>
> Is there any chance you could point me in the direction of your code 
> so I can see how the callbacks are working?  This is the area I am 
> having difficulty with (probably because I am still new to GTK).  I 
> am making a pixel-based drawing program myself, but I dont intend it 
> to compete with the GIMP - it would have more of a focus on image 
> creation rather than image manipulation.
>
> As far as the type of MDI I aim to use, it will be pretty-much like 
> the GIMP in style - ie. no tabs and no WiW.  Ideology aside, I find 
> WiW claustrophopic and I am not 100% sure that tabs are suitable for 
> images.
>
> Best regards,
>
> Chris.
>
>
> > From: Jim Parker <hopeye cfl rr com>
> > To: Chris Garrett <garrett91 hotmail com>
> > CC: gtk-app-devel-list gnome org
> > Subject: Re: Multiple documents
> > Date: Mon, 25 Aug 2003 15:00:19 -0400
> >
> > G'Day !
> >
> > I do not know if this is the best way, but I am using a linked list 
> > of struts, with each strut containing the information needed by each 
> > document (BTW I'm doing a vector drawing program).
> >
> > Works well for small numbers of documents, never tested for large 
> > sets ...
> >
> > cheers,
> > Jim Parker
> >
> >
> > On 2003.08.25 14:22 Chris Garrett wrote:
> > > Hi all,
> > >
> > > Is there a standard / recommended way to write an application that 
> > > can open more than one document at a time, and that allows more 
> > > than one view of each document (ala GIMP)?
> > >
> > > If so, is there a nice, small, simple example I can look at to get 
> > > started?  The source code to the GIMP is too large for my tired 
> > > brain at the moment :o(
> > >
> > > BTW, I am using GTK2.2
> > >
> > > Best regards,
> > >
> > > Chris.
> > >
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